Imaging apparatus, information processing apparatus and method, and computer program therefor

ABSTRACT

An imaging apparatus includes an imaging unit that captures an image; a recording unit that records the image on a recording medium; a first position estimating unit that estimates a position of the imaging apparatus using a first position estimation technique to generate first position information, and calculates a first evaluation value serving as accuracy evaluation information of the first position information; a second position estimating unit that estimates the position of the imaging apparatus using a second position estimation technique different from the first position estimation technique to generate second position information, and calculates a second evaluation value serving as accuracy evaluation information of the second position information; a position-information obtaining unit that select, from the first and second position information, position information whose evaluation value is higher than the other; and an application executing unit that performs data processing using the selected position information.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2007-151713 filed in the Japanese Patent Office on Jun.7, 2007, the entire contents of which are incorporated herein byreference.The present application is a continuation reissue applicationof U.S. application Ser. No. 14/227,478, filed Mar. 27, 2014, now U.S.Pat. No. RE45,319E, which is a Reissue of U.S. application Ser. No.12/110,764, filed Apr. 28, 2008, now U.S. Pat. No. 8,184,170, and inturn contains subject matter related to Japanese Patent Application JP2007-151713 filed in the Japanese Patent Office on Jun. 7, 2007, theentire contents of which are incorporated herein by reference. Thus,more than one reissue application has been filed for the reissue of U.S.Pat. No. 8,184,170. The reissue applications are the presentcontinuation reissue application and U.S. application Ser. No.14/227,478 (parent application).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to imaging apparatuses, informationprocessing apparatuses and methods, and computer programs therefor. Moreparticularly, the present invention relates to an imaging apparatus,such as a digital camera, including position estimating units employingdifferent techniques, in which items of position informationindividually obtained by the position estimating units are evaluated,and, position information determined to be more accurate is selectivelyused, an information processing apparatus and method, and a computerprogram therefor.

The present invention further relates to an imaging apparatus including,as position estimating units using different techniques, for example, aposition estimating unit based on the Global Positioning System (GPS)and a position estimating unit based on detection information of accesspoints (APs) serving as wireless communication base stations, in whichposition estimation results individually obtained by the positionestimating units are evaluated, and position information is used in amanner that, for example, highly evaluated result data is used asattribute data of captured image data, an information processingapparatus and method, and a computer program therefor.

2. Description of the Related Art

Nowadays, imaging apparatuses such as digital cameras have become highlysophisticated. For example, some imaging apparatuses have the GPSfunction to obtain position information using GPS and record theobtained position information as attribute information of captured imagedata.

In order to obtain position information using GPS, an imaging apparatusis necessary to be able to receive radio waves from satellites. Whenbeneath the ground, for example, the imaging apparatus is incapable ofreceiving radio waves from satellites and hence incapable of obtainingposition information. In order to obtain position information using GPS,the imaging apparatus is necessary to perform a satellite acquisitionprocess as an initial process, which takes time. That is, when aturned-off camera is switched on, the camera is incapable of immediatelyobtaining position information using GPS.

In order to reduce a wait time before position information is obtained,one method is available in which a GPS module of a camera is maintainedin an operating state, and navigation messages from satellites arecontinuously received using the GPS module. The received navigationmessages are stored in a storage unit, and satellite acquisition isperformed using the stored navigation messages. The effective period ofalmanac data contained in the navigation messages is set to threemonths, and the effective period of ephemeris data contained in thenavigation messages is set to two hours. Navigation messages stored inthe storage unit are necessary to be updated one after another. Thus, acontinuous message reception process is necessary to be performed.

A structure that can continuously receive navigation messages can updatenavigation messages recorded in a storage unit in a steady manner. Quicksatellite acquisition using navigation messages (almanac data andephemeris data) within the effective period can thus be performed.However, when no data within the effective period is recorded, efficientsatellite acquisition using the data is difficult to be performed. Thus,a satellite acquisition process involving a relatively long processingtime is necessary to be performed. As a result, the time from activationof the GPS module to the obtaining of position information becomes verylong, and hence, position information is difficult to be obtained in atimely manner.

When a camera with a GPS module performs a process of adding positioninformation obtained using the GPS module as attribute information ofcaptured image data, it is necessary to obtain position information atthe time an image is captured by a user. However, as has been describedabove, in an environment where position information is difficult to beobtained from satellites using GPS or when position information isdifficult to be immediately obtained from satellites using GPS, accurateposition information corresponding to captured image data is difficultto be obtained.

One of position estimation methods using techniques other than thoseusing GPS is described in Japanese Unexamined Patent ApplicationPublication No. 2002-107443. This method concerns a wirelesscommunication system in which a mobile device estimates its position bymeasuring the intensity of radio waves received from a base stationwhose position information has been registered in advance. In such aconfiguration where the position is measured using the base station, themobile device is incapable of measuring the position when the mobiledevice is in an area where the mobile device is incapable ofcommunicating with the base station whose position information has beenregistered.

SUMMARY OF THE INVENTION

It is desirable to provide an imaging apparatus, such as a digitalcamera, including different position estimating units, in which positionestimation results individually obtained by the position estimatingunits are evaluated, and highly evaluated result data is selectivelyobtained and used as, for example, attribute data of captured imagedata, an information processing apparatus and method, and a computerprogram therefor.

It is desirable to provide an imaging apparatus with, as differentposition estimating units, for example, a position estimating unit basedon GPS and a position estimating unit based on detection information ofAPs serving as wireless communication base stations, in which positionestimation results individually obtained by the position estimatingunits are evaluated, and position information is selected and used in amanner that, for example, highly evaluated result data is used asattribute data of captured image data, an information processingapparatus and method, and a computer program therefor.

According to a first embodiment of the present invention, there isprovided an imaging apparatus that captures an image. The imagingapparatus includes the following elements: an imaging unit configured tocapture an image; a recording unit configured to perform a process ofrecording the captured image on a recording medium; a first positionestimating unit configured to estimate a position of the imagingapparatus using a first position estimation technique to generate firstposition information, and to calculate a first evaluation value servingas accuracy evaluation information of the first position information; asecond position estimating unit configured to estimate the position ofthe imaging apparatus using a second position estimation technique togenerate second position information, the second position estimationtechnique being different from the first position estimation technique,and to calculate a second evaluation value serving as accuracyevaluation information of the second position information; aposition-information obtaining unit configured to select, from the firstposition information and the second position information, positioninformation whose evaluation value is higher than the other; and anapplication executing unit configured to perform data processing usingthe position information selected by the position-information obtainingunit.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS. The second position estimating unit may be configured togenerate the second position information by performing a positionestimation process using a technique that is different from the positionestimation process using GPS.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS. The second position estimating unit may be configured togenerate the second position information by searching for a base stationof wireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS and to calculate the first evaluation value on the basis ofmeasurement status information obtained by analyzing data received froma satellite. The second position estimating unit may be configured togenerate the second position information by searching for a base stationof wireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information, and to calculate the second evaluation value onthe basis of a reception signal level of a reception signal receivedfrom the base station at the time the base station is detected, thereception signal level corresponding to an electric field intensity.

The first position estimating unit may be configured to set a lowevaluation value in a case where the measurement status information istwo-dimensional and a high evaluation value in a case where themeasurement status information is three-dimensional.

The second position estimating unit may be configured to compare thereception signal level with a predetermined threshold and to set a highevaluation value in a case where the reception signal level is greaterthan or equal to the threshold and a low evaluation value in a casewhere the reception signal level is less than the threshold.

The application executing unit may be configured to perform a process ofrecording the position information selected by the position-informationobtaining unit as position information in a recording file of thecaptured image.

The application executing unit may be configured to perform a process ofusing the position information selected by the position-informationobtaining unit as current position information representing a currentposition on a map displayed on a display unit.

According to a second embodiment of the present invention, there isprovided an information processing apparatus including the followingelements: a first position estimating unit configured to estimate aposition of the information processing apparatus using a first positionestimation technique to generate first position information, and tocalculate a first evaluation value serving as accuracy evaluationinformation of the first position information; a second positionestimating unit configured to estimate the position of the informationprocessing apparatus using a second position estimation technique togenerate second position information, the second position estimationtechnique being different from the first position estimation technique,and to calculate a second evaluation value serving as accuracyevaluation information of the second position information; aposition-information obtaining unit configured to select, from the firstposition information and the second position information, positioninformation whose evaluation value is higher than the other; and anapplication executing unit configured to perform data processing usingthe position information selected by the position-information obtainingunit.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS. The second position estimating unit may be configured togenerate the second position information by performing a positionestimation process using a technique that is different from the positionestimation process using GPS.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS. The second position estimating unit may be configured togenerate the second position information by searching for a base stationof wireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information.

The first position estimating unit may be configured to generate thefirst position information by performing a position estimation processusing GPS and to calculate the first evaluation value on the basis ofmeasurement status information obtained by analyzing data received froma satellite. The second position estimating unit may be configured togenerate the second position information by searching for a base stationof wireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information, and to calculate the second evaluation value onthe basis of a reception signal level of a reception signal receivedfrom the base station at the time the base station is detected, thereception signal level corresponding to an electric field intensity.

According to a third embodiment of the present invention, there isprovided an information processing method performed by an informationprocessing apparatus. The method includes the steps of, with a firstposition estimating unit, estimating a position of the informationprocessing apparatus using a first position estimation technique togenerate first position information, and calculating a first evaluationvalue serving as accuracy evaluation information of the first positioninformation; with a second position estimating unit, estimating theposition of the information processing apparatus using a second positionestimation technique to generate second position information, the secondposition estimation technique being different from the first positionestimation technique, and calculating a second evaluation value servingas accuracy evaluation information of the second position information;with a position-information obtaining unit, selecting, from the firstposition information and the second position information, positioninformation whose evaluation value is higher than the other; and with anapplication executing unit, performing data processing using theselected position information.

The first position information may be generated by performing a positionestimation process using GPS. The second position information may begenerated by performing a position estimation process using a techniquethat is different from the position estimation process using GPS.

The first position information may be generated by performing a positionestimation process using GPS. The second position information may begenerated by searching for a base station of wireless communication,receiving base-station identification information from the detected basestation, and searching a database in which base-station identificationinformation is associated with position information.

The first position information may be generated by performing a positionestimation process using GPS, and the first evaluation value may becalculated on the basis of measurement status information obtained byanalyzing data received from a satellite. The second positioninformation may be generated by searching for a base station of wirelesscommunication, receiving base-station identification information fromthe detected base station, and searching a database in whichbase-station identification information is associated with positioninformation, and the second evaluation value may be calculated on thebasis of a reception signal level of a reception signal received fromthe base station at the time the base station is detected, the receptionsignal level corresponding to an electric field intensity.

When the first evaluation value is calculated, a low evaluation valuemay be set in a case where the measurement status information istwo-dimensional and a high evaluation value may be set in a case wherethe measurement status information is three-dimensional.

When the second evaluation value is calculated, the reception signallevel may be compared with a predetermined threshold, and a highevaluation value may be set in a case where the reception signal levelis greater than or equal to the threshold and a low evaluation value maybe set in a case where the reception signal level is less than thethreshold.

When the data processing is performed using the selected positioninformation, a process of recording the selected position information asposition information in a recording file of the captured image may beperformed.

When the data processing is performed using the selected positioninformation, a process of using the selected position information ascurrent position information representing a current position on a mapdisplayed on a display unit may be performed.

According to a fourth embodiment of the present invention, there isprovided a computer program for causing an information processingapparatus to perform information processing. The information processingincludes the steps of causing a first position estimating unit toestimate a position of the information processing apparatus using afirst position estimation technique to generate first positioninformation, and to calculate a first evaluation value serving asaccuracy evaluation information of the first position information;causing a second position estimating unit to estimate the position ofthe information processing apparatus using a second position estimationtechnique to generate second position information, the second positionestimation technique being different from the first position estimationtechnique, and to calculate a second evaluation value serving asaccuracy evaluation information of the second position information;causing a position-information obtaining unit to select, from the firstposition information and the second position information, positioninformation whose evaluation value is higher than the other; and causingan application executing unit to perform data processing using theselected position information.

The computer program according to the embodiment of the presentinvention is a computer program provided in a computer-readable format,using a storage medium or a communication medium, to a general-purposecomputer system that can execute various program codes. By providingsuch a program in a computer-readable format, a process associated withthe program can be executed on the computer system.

Further objects, features, and advantages of the embodiments of thepresent invention will become apparent from detailed description basedon the later-described embodiments of the present invention and theappended drawings. The term “system” in this specification is a logicalset of a plurality of apparatuses and is not limited to the structure inwhich these apparatuses are accommodated in a single housing.

According to the embodiments of the present invention, first positioninformation is generated using, for example, GPS. Second positioninformation is generated by searching for a base station of wirelesscommunication, receiving base-station identification information fromthe detected base station, and searching a database in whichbase-station identification information is associated with positioninformation. Further, evaluation values serving as accuracy evaluationinformation of the first position information and the second positioninformation are generated. Position information whose evaluation valueis higher than the other is selected and used. According to thisstructure, for example, the second position information can be used inan area where GPS is difficult to be used, such as when the imagingapparatus is beneath the ground. Further, position informationdetermined to be more accurate can be selectively used. For example,position information to be set as attribute information in the imagingapparatus can become more accurate data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the structure of and a processperformed by an imaging apparatus according to an embodiment of thepresent invention;

FIG. 2 illustrates an image file (Exif) recorded by the imagingapparatus according to the embodiment of the present invention;

FIG. 3 illustrates the structure of the imaging apparatus according tothe embodiment of the present invention and an exemplary process ofobtaining, evaluating, and using position information;

FIG. 4 is a table describing an exemplary process of evaluating positioninformation using the imaging apparatus according to the embodiment ofthe present invention;

FIG. 5 is a table describing an exemplary process of evaluating positioninformation using the imaging apparatus according to the embodiment ofthe present invention;

FIG. 6 is a diagram of a processing sequence of obtaining, evaluating,and using position information using the imaging apparatus according tothe embodiment of the present invention;

FIG. 7 is a diagram of a processing sequence of obtaining, evaluating,and using position information using the imaging apparatus according tothe embodiment of the present invention;

FIG. 8 is a diagram of a processing sequence of obtaining, evaluating,and using position information using the imaging apparatus according tothe embodiment of the present invention;

FIG. 9 is a block diagram of an exemplary structure of the imagingapparatus according to the embodiment of the present invention; and

FIG. 10 is a block diagram of an exemplary structure of the imagingapparatus according to the embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An imaging apparatus, an information processing apparatus and method,and a computer program therefor according to embodiments of the presentinvention will now herein be described in detail below with reference tothe drawings.

Referring now to FIG. 1, a process performed by an imaging apparatusserving as an example of an image processing apparatus according to anembodiment of the present invention will now be schematically described.An imaging apparatus 100 includes a plurality of position estimatingunits including a first position estimating unit 101 and a secondposition estimating unit 102 shown in FIG. 1.

These position estimating units individually perform position estimationprocesses using different methods. In the example shown in FIG. 1, thefirst position estimating unit 101 is a GPS module. The first positionestimating unit 101 receives radio waves from satellites 110a to 110cand estimates the position of the imaging apparatus 100. The secondposition estimating unit 102 is a wireless local area network (WLAN)module. The second position estimating unit 102 performs a positionestimation process based on detection information of APs 120a to 120cserving as base stations of WLAN communication, which is obtained byscanning the APs 120a to 120c. This process is described in detaillater.

In the present embodiment, as has been described above, the case whereone of the position estimating units included in the imaging apparatusestimates the position of the imaging apparatus using GPS, and the otherposition estimating unit performs a position estimation process based ondetection information of APs in WLAN is described below. However, thisis only one example. The imaging apparatus 100 is not limited to thiscombination of GPS and WLAN, and the imaging apparatus 100 can employ acombination of other position estimation techniques. Moreover, theimaging apparatus 100 may include position estimating units not onlyusing two different techniques, but also using three or more differenttechniques.

The imaging apparatus 100 of the embodiment of the present inventionevaluates items of position estimation information obtained from theposition estimating units 101 and 102 and selectively uses positionestimation information determined to be more accurate. For example, theimaging apparatus 100 adds the selected position information asattribute information to an image captured using the imaging apparatus100 and records the attribute information together with the capturedimage in a medium.

FIG. 2 illustrates an exemplary data structure of a file recorded in arecording medium on the basis of an image captured using the imagingapparatus 100. The image captured using the imaging apparatus 100 isrecorded as, for example, a file in the Exif format with the datastructure shown in FIG. 2. One file in the Exif format is set to eachitem of captured image data. As shown in FIG. 2, a file in the Exifformat includes a header 221, thumbnail data 222, and image data 223.

The thumbnail data 222 is an area for recording size-reduced image data.A list of images can be displayed using items of thumbnail data 223. Theimage data 223 is an area for recording actually captured image data.

The header 221 is an area for recording attribute information of animage. As shown in FIG. 2, the header 221 includes the number of pixels,compression mode, image capturing time and date, and further, in thisexample, position information 231. The position information 231 isselected position information determined to be more accurate byevaluating items of position estimation information obtained from theposition estimating units 101 and 102 shown in FIG. 1.

In the case where the imaging apparatus 100 has, for example, a mapdisplay application, the imaging apparatus 100 displays a map on adisplay unit included in the imaging apparatus 100 in the followingmanner. On the basis of position estimation information with a highevaluation value, which is selected from items of position estimationinformation obtained from the position estimating units 101 and 102, amap of the neighborhood of the selected position information isdisplayed, and the current position is displayed on the displayed map.The selected position information can be used in various mannersdepending on applications installed in the imaging apparatus 100 and canbe used in various other manners.

Referring now to FIG. 3, a process performed using the imaging apparatusof the embodiment of the present invention will be described. FIG. 3illustrates the overall process performed using the imaging apparatus ofthe embodiment of the present invention. Applications executing variousprocesses including, for example, a process of recording a capturedimage in a medium and a process of displaying a map on a display of theimaging apparatus are installed in the imaging apparatus of theembodiment of the present invention. Applications 301 shown at the topof FIG. 3 are applications for executing these processes. Theapplications 301 are read and executed by a control unit (such as acentral processing unit (CPU)) in accordance with a program stored in astorage unit of the imaging apparatus. An exemplary hardware structureof the imaging apparatus is described later.

In the structure shown in FIG. 3, the applications 301 at the topexecute a process of receiving, from a position-information obtainingunit (location engine) 302, position information selected as moreaccurate position information from among items of position informationobtained from a plurality of position estimating units included in theimaging apparatus and using the selected position information received.For example, the applications 301 execute a process of recording theposition information as attribute information in a file (Exif) of acaptured image, a process of displaying a map on a display, and thelike, as has been described above.

The position-information obtaining unit (location engine) 302 receives,from two different position estimating units including a first positionestimating unit (GPS-based) 311 and a second position estimating unit(AP-based) 321, items of position information (latitude and longitudeinformation) individually obtained using respective techniques andevaluation values serving as indices of accuracy of the obtainedposition information.

From the two different position estimating units including the firstposition estimating unit (GPS-based) 311 and the second positionestimating unit (AP-based) 321, the position-information obtaining unit(location engine) 302 receives the following two combinations of data:

-   (a) position information (latitude and longitude) obtained using GPS    and its evaluation value; and-   (b) position information obtained by scanning APs in WLAN and its    accuracy value.

The position-information obtaining unit (location engine) 302 comparesthe evaluation values contained in these items of data, determines thatposition information (latitude and longitude) whose evaluation value ishigher than the other is more accurate position information, selects themore accurate position information, and outputs the selected positioninformation to the applications 301.

The first position estimating unit (GPS-based) 311 outputs positioninformation (latitude and longitude) obtained using GPS and itsevaluation value to the position-information obtaining unit (locationengine) 302. A GPS module 314 receives data from satellites and sendsthe received data to a GPS decoder 312 via a GPS driver (UART driver)313. On the basis of the data received from the GPS module 314, the GPSdecoder 312 obtains, for example, latitude and longitude informationserving as position information, measurement status information(two-dimensional/three-dimensional), dispersion, and ephemeris data.Whether the measurement status is two-dimensional or three-dimensionalcorresponds to accuracy of position information that can be analyzed onthe basis of data received from satellites. When the measurement statusis two-dimensional, the corresponding position information obtained isof low accuracy. When the measurement status is three-dimensional, thecorresponding position information obtained is of high accuracy.

The first position estimating unit (GPS-based) 311 receives these itemsof data obtained by the GPS decoder 312, calculates an evaluation valuecorresponding to the position information (latitude and longitude)obtained using GPS, and outputs the position information (latitude andlongitude) obtained using GPS, together with the calculated evaluationvalue, to the position-information obtaining unit (location engine) 302.

In contrast, the second position estimating unit (AP-based) 321 outputsposition information (latitude and longitude) obtained by scanning APsin WLAN and its evaluation value to the position-information obtainingunit (location engine) 302.

A process of obtaining position information (latitude and longitude) byscanning APs is described in detail below. A WLAN module 323 included inthe imaging apparatus executes a scanning process as a process ofsearching for APs in the neighborhood of the imaging apparatus. Thescanning process is a process of searching for APs that are located inthe neighborhood where communication is possible. With the scanningprocess, data including a service set identifier (SSID) corresponding toan identifier of each AP and a media access control (MAC) address ofeach AP is obtained from each of APs that are located in theneighborhood of the imaging apparatus and that can communicate with theimaging apparatus. SSID is bit information serving as the identifierunique to each AP.

From each AP, the WLAN module 323 receives SSID serving asidentification information unique to the AP and the MAC address(electric field intensity), measures a reception signal level on thebasis of a reception signal received from the AP, and outputs theseitems of information to the second position estimating unit (AP-based)321 via a WLAN driver 322.

The second position estimating unit (AP-based) 321 outputs items ofinformation obtained from the WLAN module 323, namely, the MAC addresscorresponding to each AP, which is obtained from each of APs located inthe neighborhood of the imaging apparatus, and reception-signal-level(electric field intensity) information corresponding to each AP, to asecond-position-estimation-unit basic processor (place engine core) 324.

On the basis of these items of information, thesecond-position-estimation-unit basic processor (place engine core) 324searches a database 325 and obtains current position information(latitude and longitude) of the imaging apparatus.

The database 325 is a database in which data is registered so thatlatitude and longitude information can be obtained on the basis ofidentification information (MAC address) of each AP. For example, itemsof data including MAC address information of each AP and latitude andlongitude information of each AP are registered in a correspondingmanner in the database 325. Alternatively, items of data including oneMAC address of an AP or a combination of MAC addresses of APs andposition information obtained on the basis of the value of a receptionsignal level from the AP or a combination of the values of receptionsignal levels from the APs are registered in a corresponding manner inthe database 325.

For example, when information obtained by the WLAN module 323 includes aMAC address corresponding to one AP and a reception signal levelobtained from this particular AP, latitude and longitude informationcorresponding to this particular AP, which is associated with the MACaddress of that AP and registered in the database 325, is determined asthe current position of the imaging apparatus.

Alternatively, for example, when information obtained by the WLAN module323 includes two MAC addresses of two APs and two reception signallevels obtained from the two APs, position information is obtained fromthe database 325 on the basis of a combination of the MAC addresses ofthe two APs and a combination of the reception signal levels obtainedfrom the two APs. In the case where items of data are received from aplurality of APs in the scanning process, as has been described above, amore accurate current position can be obtained from the database 325.

The second-position-estimation-unit basic processor (place engine core)324 outputs position information (latitude and longitude) obtained fromthe database 325 to the second position estimating unit (AP-based) 321.

The second position estimating unit (AP-based) 321 receives the positioninformation (latitude and longitude) obtained by thesecond-position-estimation-unit basic processor (place engine core) 324from the database 325. Further, the second position estimating unit(AP-based) 321 receives items of information obtained by the WLAN module323, namely, the MAC address(es) corresponding to the AP(s) obtainedfrom the AP(s) detected by the scanning process in the neighborhood ofthe imaging apparatus and the reception signal level (electric fieldintensity) information corresponding to the AP(s). On the basis of theseitems of information, the second position estimating unit (AP-based) 321calculates an evaluation value of the position information (latitude andlongitude) obtained by the second-position-estimation-unit basicprocessor (place engine core) 324 from the database 325 and outputs theposition information (latitude and longitude) obtained by scanning theAP(s), together with the calculated evaluation value, to theposition-information obtaining unit (location engine) 302.

The position-information obtaining unit (location engine) 302 receives,from two different position estimating units, namely, the first positionestimating unit (GPS-based) 311 and the second position estimating unit(AP-based) 321, items of position information (latitude and longitudeinformation) individually obtained using respective techniques andevaluation values serving as indices of accuracy of the obtained itemsof position information. That is, as has been described above, theposition-information obtaining unit (location engine) 302 receives thefollowing two combinations of data:

-   (a) position information (latitude and longitude) obtained using GPS    and its evaluation value; and-   (b) position information obtained by scanning APs in WLAN and its    accuracy value.

The position-information obtaining unit (location engine) 302 comparesthe evaluation values contained in these items of data, determines thatposition information (latitude and longitude) whose evaluation value ishigher than the other is more accurate position information, selects themore accurate position information, and outputs the selected positioninformation to the applications 301.

The applications 301 receive the position information selected by theposition-information obtaining unit (location engine) 302 and perform aprocess using the received position information, such as a process ofrecording the position information as attribute information in a file(Exif) of a captured image or a process of displaying a map on adisplay, as has been described above.

The imaging apparatus of the embodiment of the present inventionperforms different position estimation methods, calculates evaluationvalues corresponding to items of position information obtained using thedifferent position estimation methods, compares the calculatedevaluation values, determines that position information whose evaluationvalue is higher than the other is more accurate position information,and selects the more accurate position information as positioninformation to be used in applications. With this process, for example,even when position information measured using GPS is of low reliability,position information obtained by searching a database on the basis of aMAC address(es) of an AP(s), which is obtained by scanning APs in WLAN,can be used.

In contrast, when position information obtained by searching a databaseon the basis of a MAC address(es) of an AP(s), which is obtained byscanning APs in WLAN, is of low reliability, position informationobtained using GPS can be used in applications.

The first position estimating unit (GPS-based) 311 and the secondposition estimating unit (AP-based) 321 each calculate an evaluationvalue corresponding to position information obtained using a respectivetechnique. Exemplary processes of calculating evaluation values aredescribed with reference to FIGS. 4 and 5.

The following description concerns an example in which an evaluationvalue of position information obtained by the first position estimatingunit (GPS-based) 311 using GPS is calculated.

As has been described, on the basis of data received by the GPS module314, the GPS decoder 312 obtains, for example, latitude and longitudeinformation serving as position information, measurement statusinformation (two-dimensional/three-dimensional), dispersion, andephemeris data. Among these items of data, the measurement status, whichis two-dimensional or three-dimensional, corresponds to accuracy ofposition information that can be analyzed on the basis of the datareceived from satellites. That is, when the measurement status istwo-dimensional, the corresponding position information obtained is oflow accuracy. When the measurement status is three-dimensional, thecorresponding position information obtained is of high accuracy. In thismanner, items of position information of different accuracy levels areobtained.

The first position estimating unit (GPS-based) 311 determines anevaluation value on the basis of, for example, the measurement status.

FIG. 4 illustrates an example in which evaluation values of items ofposition information obtained by the first position estimating unit(GPS-based) 311 using GPS are set. As shown in FIG. 4, an evaluationvalue ranges from 0 to 100 and is set in the following manner:

-   (a) when the measurement status is three-dimensional, the evaluation    value is set to 90;-   (b) when the measurement status is two-dimensional, the evaluation    value is set to 60; and-   (c) when no measurement is performed, the evaluation value is set to    0.    In the foregoing example, 0 is the lowest evaluation value, and 100    is the highest evaluation value.

On the basis of the MAC address(es) obtained by scanning the APs in WLANor on the basis of the MAC address(es) and signal level(s) (electricfield intensity), the second position estimating unit (AP-based) 321obtains position information (latitude and longitude) from the database325 and calculates an evaluation value serving as a reliability level ofthe obtained position information.

FIG. 5 illustrates an example in which evaluation values of items ofposition information obtained by the second position estimating unit(AP-based) 321 by scanning the APs are set. As shown in FIG. 5, anevaluation value ranges from 0 to 100 and is set in the followingmanner:

-   (a) when position information is successfully obtained from the    database and when at least one of the reception signal level(s)    (electric field intensity) of reception data obtained from the AP(s)    is high, that is, greater than or equal to a predetermined threshold    (Th1), the evaluation value is set to 100;-   (b) when position information is successfully obtained from the    database and when the highest reception signal level (electric field    intensity) of reception data obtained from the AP(s) is    intermediate, that is, within the range of predetermined thresholds    (Th1 and Th2), the evaluation value is set to 70;-   (c) when position information is successfully obtained from the    database and when the highest reception signal level (electric field    intensity) of reception data obtained from the AP(s) is low, that    is, less than or equal to the predetermined threshold (Th2), the    evaluation value is set to 50; and-   (d) when the obtaining of position information from the database is    unsuccessful (failed), the evaluation value is set to 0.    In the foregoing example, 0 is the lowest evaluation value, and 100    is the highest evaluation value.

The foregoing examples of setting the evaluation value are onlyexemplary, and other evaluation criteria or evaluation algorithms can beemployed.

The position-information obtaining unit (location engine) 302 receives,from two different position estimating units, namely, the first positionestimating unit (GPS-based) 311 and the second position estimating unit(AP-based) 321, items of position information (latitude and longitudeinformation) individually obtained using respective techniques andevaluation values calculated using the foregoing evaluation processes.The position-information obtaining unit (location engine) 302 comparesthe two evaluation values, determines that position information whoseevaluation value is higher than the other is more accurate positioninformation, selects the more accurate position information, and outputsthe selected position information to the applications 301.

The overall sequence of the imaging apparatus according to theembodiment of the present invention is as has been described above withreference to FIG. 3. Referring now to FIGS. 6 to 8, the more detailedprocessing sequence of each of blocks is described as follows:

-   (1) the processing sequence performed by the applications 301, the    position-information obtaining unit (location engine) 302, and the    first and second position estimating units 311 and 321 (FIG. 6);-   (2) the processing sequence performed by the position-information    obtaining unit (location engine) 302, the first position estimation    unit (GPS-based) 311, the GPS decoder 312, and the GPS module 314    (FIG. 7); and-   (3) the processing sequence performed by the position-information    obtaining unit 302, the second position estimation unit (AP-based)    321, the WLAN module 323, the second-position-estimation-unit basic    processor (place engine core) 324, and the database 325 (FIG. 8).

Referring now to FIG. 6, the detailed sequence of a process performed bythe applications 301, the position-information obtaining unit (locationengine) 302, the first position estimating unit (GPS-based) 311, and thesecond position estimating unit (AP-based) 321 is described.

In step S101, the applications 301 send a request to theposition-information obtaining unit (location engine) 302 to obtainposition information. Upon receipt of the position-information obtainingrequest, in steps S102 and S104, the position-information obtaining unit(location engine) 302 sends a request to the first position estimatingunit (GPS-based) 311 and the second position estimating unit (AP-based)321 to obtain position information. In the sequence shown in FIG. 6, instep S102, a request is sent to the second position estimating unit(AP-based) 321 to obtain position information, and, in step S104, arequest is sent to the first position estimating unit (GPS-based) 311 toobtain position information. However, these requests can be sent inparallel to each other.

In step S102, the second position estimating unit (AP-based) 321receives the position-information obtaining request from theposition-information obtaining unit (location engine) 302. As has beendescribed above, the second position estimating unit (AP-based) 321obtains position information (latitude and longitude) by searching thedatabase 325 on the basis of the MAC address(es) of the AP(s) and thereception signal level(s) (electric field intensity) obtained fromscanning information obtained by the WLAN module 323, and calculates anevaluation value of the obtained position information. In step S103, thesecond position estimating unit (AP-based) 321 outputs the positioninformation and the evaluation value to the position-informationobtaining unit (location engine) 302. The process performed by thesecond position estimating unit (AP-based) 321 as a processcorresponding to steps S102 and S103 is described in detail later withreference to FIG. 8.

In step S104, the first position estimating unit (GPS-based) 311receives the position-information obtaining request from theposition-information obtaining unit (location engine) 302. As has beendescribed above, the first position estimating unit (GPS-based) 311obtains position information (latitude and longitude) by performing ameasurement process using the GPS module 314 and calculates anevaluation value of the obtained position information. In step S105, thefirst position estimating unit (GPS-based) 311 outputs the positioninformation and the evaluation value to the position-informationobtaining unit (location engine) 302. The process performed by the firstposition estimating unit (GPS-based) 311 as a process corresponding tosteps S104 and S105 is described in detail later with reference to FIG.7.

The position-information obtaining unit (location engine) 302 receives,from two different position estimating units, namely, the first positionestimating unit (GPS-based) 311 and the second position estimating unit(AP-based) 321, items of position information (latitude and longitudeinformation) individually obtained using respective techniques andevaluation values thereof. In step S106, the position-informationobtaining unit (location engine) 302 compares the two evaluation values,determines that position information whose evaluation value is higherthan the other is more accurate position information, and selects themore accurate position information. In step S107, theposition-information obtaining unit (location engine) 302 outputs theselected position information to the applications 301.

In step S108, the applications 301 use the position information receivedfrom the position-information obtaining unit (location engine) 302 forprocesses of applications. For example, as has been described above, theapplications 301 perform a process of recording the position informationas attribute information in a file (Exif) of a captured image or aprocess of displaying a map of the position corresponding to theobtained position information on a display.

Referring now to FIG. 7, the detailed sequence of a process performed bythe position-information obtaining unit (location engine) 302, the firstposition estimating unit (GPS-based) 311, the GPS decoder 312, and theGPS module 314 is described. This process corresponds to a detailedprocess performed by the foregoing elements in order to perform stepsS104 and S105 shown in FIG. 6. Step S205 shown in FIG. 7 corresponds tostep S104 shown in FIG. 6, that is, a position-information obtainingrequest sent from the position-information obtaining unit (locationengine) 302. Step S209 shown in FIG. 7 corresponds to step S105 shown inFIG. 6, that is, a process of outputting position information and itsevaluation value from the first position estimating unit (GPS-based) 311to the position-information obtaining unit (location engine) 302.

Steps S201 to S204 shown in FIG. 7 correspond to a process continuouslyperformed in the case where the GPS module 314 is in an operating state.Alternatively, the process may be performed in response to aninstruction given from the position-information obtaining unit (locationengine) 302.

In step S201, the GPS module 314 receives radio waves from satellitesand performs a measurement process. In step S202, the GPS module 314outputs items of information obtained as measurement results to the GPSdecoder 312. The items of information obtained as the measurementresults include, for example, latitude and longitude information servingas position information, measurement status information(two-dimensional/three-dimensional), dispersion, and ephemeris data.

Upon receipt of these items of information from the GPS module 314, instep S203, the GPS decoder 312 analyzes the received items ofinformation. The analysis includes an analysis of the latitude andlongitude information, an analysis of the measurement status information(two-dimensional/three-dimensional), an analysis of the dispersioninformation, an analysis of the ephemeris data, and an analysis of otherinformation. In step S204, the GPS decoder 312 stores the analysisresults in a memory.

Steps S201 to S204 correspond to a process continuously performed in thecase where, as has been described above, the GPS module 314 is in anoperating state. With this continuous measurement process, informationsuch as position information recorded in the memory is periodicallyupdated, and data based on the latest measurement information is storedin the memory.

In step S205, the position-information obtaining unit (location engine)302 sends a request to the first position estimating unit (GPS-based)311 to obtain position information. In response to this, in step S206,the first position estimating unit (GPS-based) 311 outputs a request tothe GPS decoder 312 to obtain position information.

Upon receipt of the position-information obtaining request from thefirst position estimating unit (GPS-based) 311, in step S207, the GPSdecoder 312 outputs the analysis results stored in the memory, whichserve as the latest data stored in the memory at that point, to thefirst position estimating unit (GPS-based) 311. The output items ofinformation include, for example, the latest position information(latitude and longitude) obtained by the GPS module 314 and themeasurement status (two-dimensional/three-dimensional).

Upon receipt of data such as the position information from the GPSdecoder 312, in step S208, the first position estimating unit(GPS-based) 311 evaluates the position information. This evaluationprocess is performed on the basis of, for example, as has been describedabove with reference to FIG. 4, the measurement status. As shown in FIG.4, an evaluation value ranges from 0 to 100 and is set in the followingmanner:

-   (a) when the measurement status is three-dimensional, the evaluation    value is set to 90;-   (b) when the measurement status is two-dimensional, the evaluation    value is set to 60; and-   (c) when no measurement is performed, the evaluation value is set to    0.

In step S209, the first position estimating unit (GPS-based) 311 outputsthe position information (latitude and longitude) obtained by performingthe measurement process using the GPS module 314 and the evaluationvalue calculated by the foregoing process to the position-informationobtaining unit (location engine) 302.

Referring now to FIG. 8, the detailed sequence of a process performed bythe position-information obtaining unit (location engine) 302, thesecond position estimating unit (AP-based) 321, the WLAN module 323, thesecond-position-estimation-unit basic processor (place engine core) 324,and the database 325 is described. This process corresponds to adetailed process performed by the foregoing elements in order to performsteps S102 and S103 shown in FIG. 6. Step S310 shown in FIG. 8corresponds to step S102 shown in FIG. 6, that is, aposition-information obtaining request sent from theposition-information obtaining unit (location engine) 302. Step S311shown in FIG. 8 corresponds to step S103 shown in FIG. 6, that is, aprocess of outputting position information and its evaluation value fromthe second position estimating unit (AP-based) 321 to theposition-information obtaining unit (location engine) 302.

Steps S301 to S309 shown in FIG. 8 corresponds to a process that can beperformed in the case where the WLAN module 323 is in an operatingstate. The process can be performed regardless of the presence ofinstructions given from the upper-level applications 301 or theposition-information obtaining unit (location engine) 302.Alternatively, the process may be performed in response to aninstruction given from the position-information obtaining unit (locationengine) 302.

In step S301, the second position estimating unit (AP-based) 321 outputsa scan execution request to the WLAN module 323. In step S302, the WLANmodule 323 executes a scanning process serving as a process of searchingfor APs that are located in the neighborhood of the imaging apparatus.

With the scanning process, the WLAN module 323 receives SSID serving asthe identifier and the MAC address of each of the APs located in theneighborhood. Further, the WLAN module 323 measures a reception signallevel (electric field intensity) on the basis of a reception signalobtained from each AP. In step S303, the WLAN module 323 outputs theseitems of information to the second position estimating unit (AP-based)321.

In step S304, the second position estimating unit (AP-based) 321 outputsthe information obtained from the WLAN module 323, that is, the MACaddress according to each AP, which is obtained from each of the APslocated in the neighborhood, and reception-signal-level (electric fieldintensity) information corresponding to each AP, to thesecond-position-estimation-unit basic processor (place engine core) 324.

In step S305, the second-position-estimation-unit basic processor (placeengine core) 324 searches the database 325 on the basis of the MACaddress(es) of the AP(s) detected by performing the scanning process oron the basis of the MAC address(es) and the reception signal level(s)(electric field intensity). In step S306, thesecond-position-estimation-unit basic processor (place engine core) 324obtains latitude and longitude information corresponding to the AP(s),which is registered in the database 325, as the current position of theimaging apparatus.

In step S307, the second-position-estimation-unit basic processor (placeengine core) 324 outputs the position information (latitude andlongitude) obtained from the database 325 to the second positionestimating unit (AP-based) 321.

In step S308, the second position estimating unit (AP-based) 321calculates an evaluation value of the position information obtained bythe second-position-estimation-unit basic processor (place engine core)324 from the database 325.

The evaluation value is calculated on the basis of the informationobtained by the WLAN module 323, that is, the MAC address(es) of theAP(s) obtained from the AP(s) detected by the scanning process in theneighborhood of the imaging apparatus and the reception signal level(electric field intensity) information corresponding to the AP(s). Thatis, as has been described above with reference to FIG. 5, an evaluationvalue ranges from 0 to 100 and is set in the following manner:

-   (a) when position information is successfully obtained from the    database and when at least one of the reception signal level(s)    (electric field intensity) of reception data obtained from the AP(s)    is high, that is, greater than or equal to a predetermined threshold    (Th1), the evaluation value is set to 100;-   (b) when position information is successfully obtained from the    database and when the highest reception signal level (electric field    intensity) of reception data obtained from the AP(s) is    intermediate, that is, within the range of predetermined thresholds    (Th1 and Th2), the evaluation value is set to 70;-   (c) when position information is successfully obtained from the    database and when the highest reception signal level (electric field    intensity) of reception data obtained from the AP(s) is low, that    is, less than or equal to the predetermined threshold (Th2), the    evaluation value is set to 50; and-   (d) when the obtaining of position information from the database is    unsuccessful (failed), the evaluation value is set to 0.

In step S309, the second position estimating unit (AP-based) 321 storesdata including the measurement results and evaluation values in amemory. Steps S301 to S309 correspond to a process that can be performedin the case where the WLAN module 323 is in an operating state. Withthis process, information such as position information recorded in thememory can be periodically updated, and the latest position informationand its evaluation value are stored in the memory on a constant basis.

When the position-information obtaining unit (location engine) 302 sendsa position-information obtaining request to the second positionestimating unit (AP-based) 321 in step S310, the second positionestimating unit (AP-based) 321 outputs, in step S311, the obtainedposition information (latitude and longitude) and the evaluation valuecalculated by the foregoing process to the position-informationobtaining unit (location engine) 302.

With the processes described with reference to FIGS. 7 and 8, theposition-information obtaining unit (location engine) 302 receives, fromtwo different position estimating units, namely, the first positionestimating unit (GPS-based) 311 and the second position estimating unit(AP-based) 321, items of position information (latitude and longitudeinformation) individually obtained using respective techniques andevaluation values thereof. The position-information obtaining unit(location engine) 302 compares the two evaluation values, determinesthat position information whose evaluation value is higher than theother is more accurate position information, selects the more accurateposition information, and outputs the selected position information tothe applications 301. The applications 301 use the position informationreceived from the position-information obtaining unit (location engine)302 in performing processes of applications. That is, for example, theapplications 301 perform a process of recording the position informationas attribute information in a file (Exif) of a captured image or aprocess of displaying a map of the position corresponding to theobtained position information on a display.

With reference to FIG. 9, an exemplary hardware structure of the imagingapparatus according to the embodiment of the present invention isdescribed. FIG. 9 is a block diagram of an exemplary structure of theimaging apparatus according to the embodiment of the present invention.The imaging apparatus records captured image data obtained using animaging unit 510 including a charge-coupled device (CCD) 511 and asignal processor 512 in a recording medium 525 via arecording/reproducing unit 520 including a codec 521 and arecording/reproducing interface (I/F) 522. A file of a captured imagerecorded in the recording medium 525 is a file in the Exif format, whichhas been described above with reference to FIG. 2. In this file,position information is recorded as attribute information.

Position-information obtaining processes using different methods areperformed by a combination of a first position-information estimatingunit 570 and a GPS module 571 and a combination of a secondposition-information estimating unit 580 and a WLAN module 581 shown inFIG. 9. More specifically, the combination of the firstposition-information estimating unit 570 and the GPS module 571 performsa GPS-based position-information obtaining process, and the combinationof the second position-information estimating unit 580 and the WLANmodule 581 performs an AP-based position-information obtaining process.That is, the latter combination of the second position-informationestimating unit 580 and the WLAN module 581 performs aposition-information obtaining process by searching aposition-information database 585 on the basis of a MAC address(es) ofthe AP(s) detected by scanning the AP(s) or on the basis of the MACaddress(es) and a reception signal level(s) (electric field intensity).

The first position-information estimating unit 570 performs theGPS-based position-information obtaining process to obtain GPS-basedposition information and calculates its evaluation value. The secondposition-information estimating unit 580 performs the AP-basedposition-information obtaining process to obtain AP-based positioninformation and calculates its evaluation value.

The first position-information estimating unit 570 and the GPS module571 shown in FIG. 9 correspond to a structure including all of the firstposition estimating unit 311, the GPS decoder 312, the GPS driver 313,and the GPS module 314 shown in FIG. 3. The second position-informationestimating unit 580 and the WLAN module 581 shown in FIG. 9 correspondto a structure including all of the second position estimating unit 321,the WLAN driver 322, the WLAN module 323, and thesecond-position-estimation-unit basic processor 324 shown in FIG. 3. Theposition-information database 585 shown in FIG. 9 corresponds to thedatabase 325 shown in FIG. 3.

A process performed by the applications 301 and the position-informationobtaining unit 302 shown in FIG. 3 is executed as a process performed bya control unit 530 shown in FIG. 9. As shown in FIG. 9, the control unit530 includes a position-information obtaining unit (location engine) 531and an application executing unit 532. The control unit 530 performs theprocess to serve as the position-information obtaining unit (locationengine), as has been described above with reference to FIG. 3 and thelike, and processes of applications.

More specifically, the position-information obtaining unit (locationengine) 531 of the control unit 530 receives, from two differentposition estimating units, namely, the first position-informationestimating unit (GPS-based) 570 and the second position-informationestimating unit (AP-based) 580, items of position information (latitudeand longitude information) individually obtained using respectivetechniques and evaluation values thereof. The position-informationobtaining unit (location engine) 531 compares the two evaluation values,determines that position information whose evaluation value is higherthan the other is more accurate position information, and selects themore accurate position information.

The selected position information is supplied to the applicationexecuting unit 532 of the control unit 530. The application executingunit 532 uses the position information in performing processes ofapplications. That is, for example, the application executing unit 532performs a process of recording position information that is generatedin association with a captured image as attribute information in a file(Exif) of the captured image or a process of displaying a map displayedon a display unit 545 via a display controller 546 as a map of theposition corresponding to the obtained position information.

The control unit 530 also controls other processes performed by theimaging apparatus, such as an image capturing process, an imagerecording process, and an image reproducing process. Programs of theprocesses performed by the control unit 530 are stored in a read-onlymemory (ROM) 541 or in another recording unit. Further, the imagingapparatus includes a random access memory (RAM) 542 used as, forexample, a work area for the programs or a storage area of parameters;an operation input unit 543 including a shutter and various operationunits; an operation input I/F 544; the display unit 545 for displayingimages represented by captured image data, maps, and the like; thedisplay controller 546; a memory card 547 used as a storage unit forstoring various items of data, programs, and the like; and a memory I/F548.

The process performed by the first position-information estimating unit570 and the second position-information estimating unit 580 shown inFIG. 9 may be performed by the control unit (CPU) 530, as shown in FIG.10. That is, the control unit 530 includes a first position-informationestimating unit 601 and a second position-information estimating unit602 shown in FIG. 10. Further, the database used by the secondposition-information estimating unit 602 may be formed of, for example,position-information databases 611 and 612 shown in FIG. 10. That is,the database may be set in the ROM 541 and the memory card 547.

In the foregoing embodiment, the case in which the first positionestimating unit performs position estimation by receiving radio wavesfrom satellite using the GPS module, and the second position estimatingunit performs a position estimation process based on detectioninformation obtained by scanning APs using the WLAN module has beendescribed above. However, the described case is only an example, and theimaging apparatus 100 is not limited to this combination of GPS andWLAN. Alternatively, the imaging apparatus 100 may employ a combinationof other position estimation techniques.

For example, the imaging apparatus 100 may employ a position detectionprocess based on communication with base stations of cellular phones andpersonal handy phones. Further, it is preferable that the imagingapparatus 100 be implemented according to various wireless LANstandards. For example, the IEEE 802.16 standards specify the use of afrequency band from 10 GHz to 66 GHz. In contrast, WorldwideInteroperability for Microwave Access (WIMAX) defined by IEEE 802.16aspecifies the use of a frequency band from 2 GHz to 11 GHz. According tothese frequency bands used, for example, the manner of evaluatingposition information of detected APs may be changed. In this manner, itis preferable that changes be made according to the types ofcommunication performed.

The present invention has been described in detail with reference to thespecific embodiments. However, it should be understood by those skilledin the art that various modifications, combinations, sub-combinations,and alterations may occur depending on design requirements and otherfactors insofar as they are within the scope of the appended claims orthe equivalents thereof. The scope of the present invention should bedetermined on the basis of the claims.

The series of processes described herein can be executed by hardware, bysoftware, or by a combination of hardware and software. When the seriesof processes is executed by software, a program defining the processingsequences is executed by installing it on a memory of a computerembedded in dedicated hardware or on a general-purpose computer that iscapable of executing various processes. For example, the program may berecorded in advance on a recording medium. Besides installing theprogram from the recording medium onto a computer, the program may bereceived via a network such as a LAN or the Internet and may beinstalled on a recording medium such as a built-in hard disk.

The processes described in this specification may be executed timesequentially according to the description, or may be executed inparallel or individually depending on the processing performance of anapparatus executing the processes or according to the necessity.

What is claimed is:
 1. An imaging apparatus that captures an image,comprising: an imaging unit configured to capture an image; a recordingunit configured to perform a process of recording the captured image ona recording medium; a first position estimating unit configured toestimate a position of the imaging apparatus using a first positionestimation technique to generate first position information, and tocalculate a first evaluation value serving as accuracy evaluationinformation of the first position information; a second positionestimating unit configured to estimate the position of the imagingapparatus using a second position estimation technique to generatesecond position information, the second position estimation techniquebeing different from the first position estimation technique, and tocalculate a second evaluation value serving as accuracy evaluationinformation of the second position information; a position-informationobtaining unit configured to select, from the first position informationand the second position information, position information whoseevaluation value is higher than the other; and an application executingunit configured to perform data processing using the positioninformation selected by the position-information obtaining unit.
 2. Theimaging apparatus according to claim 1, wherein the first positionestimating unit is configured to generate the first position informationby performing a position estimation process using the Global PositioningSystem; and wherein the second position estimating unit is configured togenerate the second position information by performing a positionestimation process using a technique that is different from the positionestimation process using the Global Positioning System.
 3. The imagingapparatus according to claim 1, wherein the first position estimatingunit is configured to generate the first position information byperforming a position estimation process using the Global PositioningSystem; and wherein the second position estimating unit is configured togenerate the second position information by searching for a base stationof wireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information.
 4. The imaging apparatus according to claim 1,wherein the first position estimating unit is configured to generate thefirst position information by performing a position estimation processusing the Global Positioning System and to calculate the firstevaluation value on the basis of measurement status information obtainedby analyzing data received from a satellite; and wherein the secondposition estimating unit is configured to generate the second positioninformation by searching for a base station of wireless communication,receiving base-station identification information from the detected basestation, and searching a database in which base-station identificationinformation is associated with position information, and to calculatethe second evaluation value on the basis of a reception signal level ofa reception signal received from the base station at the time the basestation is detected, the reception signal level corresponding to anelectric field intensity.
 5. The imaging apparatus according to claim 4,wherein the first position estimating unit is configured to set a lowevaluation value in a case where the measurement status information istwo-dimensional and a high evaluation value in a case where themeasurement status information is three-dimensional.
 6. The imagingapparatus according to claim 4, wherein the second position estimatingunit is configured to compare the reception signal level with apredetermined threshold and to set a high evaluation value in a casewhere the reception signal level is greater than or equal to thethreshold and a low evaluation value in a case where the receptionsignal level is less than the threshold.
 7. The imaging apparatusaccording to claim 1, wherein the application executing unit isconfigured to perform a process of recording the position informationselected by the position-information obtaining unit as positioninformation in a recording file of the captured image.
 8. The imagingapparatus according to claim 1, wherein the application executing unitis configured to perform a process of using the position informationselected by the position-information obtaining unit as current positioninformation representing a current position on a map displayed on adisplay unit.
 9. An information processing apparatus comprising: a firstposition estimating unit configured to estimate a position of theinformation processing apparatus using a first position estimationtechnique to generate first position information, and to calculate afirst evaluation value serving as accuracy evaluation information of thefirst position information; a second position estimating unit configuredto estimate the position of the information processing apparatus using asecond position estimation technique to generate second positioninformation, the second position estimation technique being differentfrom the first position estimation technique, and to calculate a secondevaluation value serving as accuracy evaluation information of thesecond position information; a position-information obtaining unitconfigured to select, from the first position information and the secondposition information, position information whose evaluation value ishigher than the other; and an application executing unit configured toperform data processing using the position information selected by theposition-information obtaining unit.
 10. The information processingapparatus according to claim 9, wherein the first position estimatingunit is configured to generate the first position information byperforming a position estimation process using the Global PositioningSystem; and wherein the second position estimating unit is configured togenerate the second position information by performing a positionestimation process using a technique that is different from the positionestimation process using the Global Positioning System.
 11. Theinformation processing apparatus according to claim 9, wherein the firstposition estimating unit is configured to generate the first positioninformation by performing a position estimation process using the GlobalPositioning System; and wherein the second position estimating unit isconfigured to generate the second position information by searching fora base station of wireless communication, receiving base-stationidentification information from the detected base station, and searchinga database in which base-station identification information isassociated with position information.
 12. The information processingapparatus according to claim 9, wherein the first position estimatingunit is configured to generate the first position information byperforming a position estimation process using the Global PositioningSystem and to calculate the first evaluation value on the basis ofmeasurement status information obtained by analyzing data received froma satellite; and wherein the second position estimating unit isconfigured to generate the second position information by searching fora base station of wireless communication, receiving base-stationidentification information from the detected base station, and searchinga database in which base-station identification information isassociated with position information, and to calculate the secondevaluation value on the basis of a reception signal level of a receptionsignal received from the base station at the time the base station isdetected, the reception signal level corresponding to an electric fieldintensity.
 13. An information processing method performed by aninformation processing apparatus, comprising the steps of: with a firstposition estimating unit, estimating a position of the informationprocessing apparatus using a first position estimation technique togenerate first position information, and calculating a first evaluationvalue serving as accuracy evaluation information of the first positioninformation; with a second position estimating unit, estimating theposition of the information processing apparatus using a second positionestimation technique to generate second position information, the secondposition estimation technique being different from the first positionestimation technique, and calculating a second evaluation value servingas accuracy evaluation information of the second position information;with a position-information obtaining unit, selecting, from the firstposition information and the second position information, positioninformation whose evaluation value is higher than the other; and with anapplication executing unit, performing data processing using theselected position information.
 14. The information processing methodaccording to claim 13, wherein the first position information isgenerated by performing a position estimation process using the GlobalPositioning System; and wherein the second position information isgenerated by performing a position estimation process using a techniquethat is different from the position estimation process using the GlobalPositioning System.
 15. The information processing method according toclaim 13, wherein the first position information is generated byperforming a position estimation process using the Global PositioningSystem; and wherein the second position information is generated bysearching for a base station of wireless communication, receivingbase-station identification information from the detected base station,and searching a database in which base-station identificationinformation is associated with position information.
 16. The informationprocessing method according to claim 13, wherein the first positioninformation is generated by performing a position estimation processusing the Global Positioning System, and the first evaluation value iscalculated on the basis of measurement status information obtained byanalyzing data received from a satellite; and wherein the secondposition information is generated by searching for a base station ofwireless communication, receiving base-station identificationinformation from the detected base station, and searching a database inwhich base-station identification information is associated withposition information, and the second evaluation value is calculated onthe basis of a reception signal level of a reception signal receivedfrom the base station at the time the base station is detected, thereception signal level corresponding to an electric field intensity. 17.The information processing method according to claim 16, wherein, whenthe first evaluation value is calculated, a low evaluation value is setin a case where the measurement status information is two-dimensionaland a high evaluation value is set in a case where the measurementstatus information is three-dimensional.
 18. The information processingmethod according to claim 16, wherein, when the second evaluation valueis calculated, the reception signal level is compared with apredetermined threshold, and a high evaluation value is set in a casewhere the reception signal level is greater than or equal to thethreshold and a low evaluation value is set in a case where thereception signal level is less than the threshold.
 19. The informationprocessing method according to claim 13, wherein, when the dataprocessing is performed using the selected position information, aprocess of recording the selected position information as positioninformation in a recording file of the captured image is performed. 20.The information processing method according to claim 13, wherein, whenthe data processing is performed using the selected positioninformation, a process of using the selected position information ascurrent position information representing a current position on a mapdisplayed on a display unit is performed.
 21. An information processingapparatus, comprising: processing circuitry; and a computer-readable,non-transitory storage storing instructions that, when executed by theprocessing circuitry, control the processing circuitry to receive alocation request from an application executed in the informationprocessing apparatus to identify an estimated position of theinformation processing apparatus, obtain a first, GPS-based positionestimate of the information processing apparatus and a first evaluationvalue representing an accuracy of the first position estimate, the firstevaluation value being determined from whether the first positionestimate is two-dimensional or three-dimensional, obtain a second,access-point-based position estimate of the information processingapparatus and a second evaluation value representing an accuracy of thesecond position estimate, the second position estimate being based onstored position information and a result of a scan for wirelesstransmissions from a plurality of access points, the stored informationincluding latitude and longitude information of the plurality of accesspoints, and select the estimated position from a more accurate of thefirst position estimate and the second position estimate.
 22. Theinformation processing apparatus of claim 21, wherein the scan forwireless transmissions is provided in a predetermined frequency bandthat includes frequencies at least 2 GHz or higher.
 23. The informationprocessing apparatus of claim 22, wherein the predetermined frequencyband is included in a range of 2 GHz through 11 GHz.
 24. The informationprocessing apparatus of claim 21, wherein the second position estimateis based on access point position information that has been stored in astorage device and that has been periodically updated.
 25. Theinformation processing apparatus of claim 21, wherein the instructionsinclude instructions to obtain the second position estimate by using aposition evaluation process for a detected access point depending on acommunication frequency band being used.
 26. The information processingapparatus of claim 21, wherein the instructions further includeinstructions to: obtain a third position estimate of the informationprocessing apparatus, and select the estimated position from a moreaccurate of the first position estimate, the second position estimateand the third position estimate.
 27. The information processingapparatus of claim 21, wherein the instructions further includeinstructions to: compare the first evaluation value with the secondevaluation value, and select the estimated position based on acomparison result.
 28. An information processing system, comprising:processing circuitry; and a computer-readable, non-transitory storagestoring instructions that, when executed by the processing circuitry,control the processing circuitry to receive a location request from anapplication executed in an information processing apparatus to identifyan estimated position of the information processing apparatus, obtain afirst, GPS-based position estimate of the information processingapparatus and a first evaluation value representing an accuracy of thefirst position estimate, the first evaluation value being determinedfrom whether the first position estimate is two-dimensional orthree-dimensional, obtain a second, access-point-based position estimateof the information processing apparatus and a second evaluation valuerepresenting an accuracy of the second position estimate, the secondposition estimate being based on stored position information and aresult of a scan for wireless transmissions from a plurality of accesspoints, the stored information including latitude and longitudeinformation of the plurality of access points, and select the estimatedposition from a more accurate of the first position estimate and thesecond position estimate, wherein the instructions include instructionsto output a command to display a map on a display device based on theestimated position.
 29. The information processing system of claim 28,wherein the scan for wireless transmissions is provided in apredetermined frequency band that includes frequencies at least 2 GHz orhigher.
 30. The information processing system of claim 29, wherein thepredetermined frequency band is included in a range of 2 GHz through 11GHz.
 31. The information processing system of claim 28, wherein thesecond position estimate is based on access point position informationthat has been stored in a storage device and that has been periodicallyupdated.
 32. The information processing system of claim 28, wherein thecircuitry is configured to obtain the second position estimate by usinga position evaluation process for a detected access point depending on acommunication frequency band being used.
 33. The information processingsystem of claim 28, wherein the instructions further includeinstructions to: obtain a third position estimate of the informationprocessing apparatus, and select the estimated position from a moreaccurate of the first position estimate, the second position estimateand the third position estimate.
 34. The information processing systemof claim 28, wherein the instructions further include instructions to:compare the first evaluation value with the second evaluation value, andselect the estimated position based on a comparison result.
 35. Aninformation processing system, comprising: processing circuitry; and acomputer-readable, non-transitory storage storing instructions that,when executed by the processing circuitry, control the processingcircuitry to receive a location request from an application executed inan information processing apparatus to identify an estimated position ofthe information processing apparatus, obtain a first, GPS-based positionestimate of the information processing apparatus and a first evaluationvalue representing an accuracy of the first position estimate, the firstevaluation value being determined from whether the first positionestimate is two-dimensional or three-dimensional, obtain a second,access-point-based position estimate of the information processingapparatus and a second evaluation value representing an accuracy of thesecond position estimate, the second position estimate being based onstored position information and a result of a scan for wirelesstransmissions from a plurality of access points, the stored informationincluding latitude and longitude information of the plurality of accesspoints, select the estimated position from a more accurate of the firstposition estimate and the second position estimate, and associate in animage file having an EXIF file format the estimated position with acaptured image, wherein the estimated position is a position at a timeof image capture.
 36. The information processing system of claim 35,wherein the scan for wireless transmissions is provided in apredetermined frequency band that includes frequencies at least 2 GHz orhigher.
 37. The information processing system of claim 36, wherein thepredetermined frequency band is included in a range of 2 GHz through 11GHz.
 38. The information processing system of claim 35, wherein thesecond position estimate is based on access point position informationthat has been stored in a storage device and that has been periodicallyupdated.
 39. The information processing system of claim 35, wherein theinstructions include instructions to obtain the second position estimateby using a position evaluation process for a detected access pointdepending on a communication frequency band being used.
 40. Theinformation processing system of claim 35, wherein the instructionsfurther include instructions to: obtain a third position estimate of theinformation processing apparatus, and select the estimated position froma more accurate of the first position estimate, the second positionestimate and the third position estimate.
 41. The information processingsystem of claim 35, wherein the instructions further includeinstructions to: compare the first evaluation value with the secondevaluation value, and select the estimated position based on acomparison result.